Prospect will meet with its ATC reps committee next week to agree further industrial action.
David Avery, Prospect negotiations officer, said:
“Our members agreed to cancel strike action earlier in the year to allow the company to develop new proposals. It is disappointing that after three meetings no new proposals have been tabled and no new money has been made available.
“Prospect members have been extremely patient with HIAL. That patience is now exhausted. We will now move to further industrial action including possible strike action. We urge Scottish Ministers to intervene and come forward with additional funding to resolve this dispute.”